Flat-lapping machine



Nov. 2 1926. 1,605,134

F. G. MUNSON FLAT LAPPING MACHINE Filed April 14, 1924 2 Sheets-Sheet 1 Nov. 2 1926. 1,605,134-

F. G. MUNSON FLAT LAPPING MACHINE F l pril 14. 1924 L 2 Sheets-Sheet 2 QVJ' 26 A iiameys.

Patented Nov. 2, 1926.

UNITED STATES FRED G. MUNSON, F WORCESTER, MASSACHUSETTS. I

' FLAT-LAPPING MACHINE.

Application filed April 14, 1924. 7 Serial No, 706,229.

This invention relates to a machine for lapping flat articles, that is, articles having opposite surfaces in parallel planes.

The principal obj ectof the invention is to provide a lapping motion which will permit of the movement of a spider, receiving the flat articles to be lapped, so compounded that each point on each article will move around a center with a slightly progressive motion and that center will also have a rotation about another center and progress around the circle in an even'and uniform manner so as to provide for equally affecting every point on the surfaces to be taken down and also to prevent. action on these surfaces in parallel lines at adjacent points. The latter effect is secured by the motion above described and it results in the provision of minute marks on the surfaces of the article which criss-cross each other in every direction and are of substantially the same spacing at all points. The degree of overlap of the successive circles and therefore the rate of progress around the second center can be varied. i

The invention also involves the movement of the articles to be lapped in such a way that it passes clear across the two opposite lapping surfaces so that the lapping action itself keeps the operative surfaces of the lapping wheels in uniform condition at all times and they do not need regrinding after they have been used.

More in detail the invention involves the use of a stationary lapping wheel above and a lapping wheel below which preferably is stationary. The motion of the articles to be operated upon is provided by rotating a spindle on an axis which may be adjustable to a certain degree but is always parallel with the axis of rotation and connecting the spider holding the work with this spindle by means of a plurality of pins eccentrically mounted thereon so as to secure the abovementioned motion. In lapping flat surfaces the above .mentioned spindle is moved off the center of rotation of the driving spindle.

Reference is to be had to the accompanying drawings, in which p Fig. 1 is a side view of a flat lapping machine showing thenew parts thereof in central vertical section;

Fig. 2 is a sectional view of a part of the operating mechanism on enlarged scale show-,

ing the gearing, etc. inside elevation; and

Figs. 3 and 4 are plan views thereof with the top lapping wheel removed and the work spider in different positions and illustratin the motion of the center point of apiece 0 fiat work held in position in the spider.

I haveshown the invention as applied to a type ofmachine which is now in use for lapping pinsor other surfaces of rotation although this invention can be used independently of the features of that machine. As so constructed that machine involves a base having a main shaft thereon receiving power through tight and loose pulleys 11 thereon. A belt shift rod 12 is adapted to be operated by a treadle 14 through a link 13. From this-base there extends upwardly a column 15 on which is a head 16 having a radial arm carrying a hand wheel 17 connect-ed with a pinion for operating a rack 18 up and down in a guide 19 on the head. This rack at the bottom is connected with a spider 20 which carries a lapping wheel 21. This wheel does notrotate but it is adapted to be raised and lowered by the hand wheel and rack and pinion.

On the base, 10 is supported a stationary support for receiving therein a stationary shaft 26. Mounted to rotate on this shaft and supported by ball bearings is a frame 27 having a worm gear 28 thereon adapted to be rotated constantly by a worm not shown, but located on the main shaft on which the tight pulley 11 is fixed. This frame 27 therefore rotates constantly when the machine is in operation. It is spaced from the stationary shaft 26 by a pair of bushings 29.

On this constantly rotating frame 27 at a distance from the center is a vertical fixed shaft 30 which carries a bushing 24 to which I are keyed two integral pinions 31 and 32. The lower one of "these pinions meshes with a gear 33 fixed on the stationary shaft 26 and therefore incapable. of. rotating. The pinion 32 meshes with another gear 34which may be swung around into axial alignment with the gear 33 for pin lapping but which may be turned away from it around the center of the shaft 30. This gear is fixed on the bottom of a shaft 43 carried centrally by a head 35 which has two pins 86 extending up from it for engaging in correspond ing perforations in a. spider 37 for holding the work W. V y

The head 35 and gear 34 are mounted to rotate about the centerof a plate 40 which ter of rotation of the cage.

itself is mounted to turn on the shaft 30 as a center through a short are and it is provided with arcuate slots 4L1 for fastening screws 12 located on the frame 27. Therefore this plate can be swung around so that the gear 34f will be out of axial alignment with the gear 33 and the plate can then be fixed in this adjusted position.

The work spider is made like any lapping machine spider having openings therethrough for the work and it is of course thinner than the work so that the work engages the lapping wheel 21 above it and also the lapping wheel 38 below it. This lapping wheel 38 is fixed on a frame 39 which is a fixed part of the machine. Both lapping wheels are stationary while the work moves.

In the operation of the machine the work holding spider 37 is placed over the pins 36 after the head 35 has been adjusted to the proper angle and the plate 40 fastened in adjusted position. Then the operation of the main shaft and the rotation of the frame 27 will cause the spider to be given a combined motion of rotation in which any point on the work itself will trace a curve such as that indicated by the heavy lines L in Figs. 3 and a. In Fig. 3 the plate 40 is adjusted around as far as it will go but of course it can be adjusted to any intermediate point. The heavy line L just referred to represents the center of a disc W constituting the work and shows the path which the enter of this piece traverses as the spider rotates. it will be seen that the work itself, especially by reference to Fig. l, moves throughout the cutting surfaces of the two stationary wheels 21 and 38 and laps over their edges so that it will wear these surfaces straight and uniform and they will not be grooved by the operation of the ma chine. Four positions of the circular piece of work W are indicated in Fig. 4 showing more clearly the way in which the work progresses around the wheels. This path of the work is important as it gets an absolutely uniform wear upon it and also upon the lapping wheels. Each point on each article being operated upon moves around a. center nearly in a circle but with a slightly progressive motion and that center also has a rotation about a second center 43 and progresses around a circle in an even and'uniform manner. The article describes a series of approximate circles in a plane progressively overlapping each other in a larger circle substantially concentric with the cen- The work itself also rotates on-its own axis as it travels, This is due to the fact that the edge farthest from the center d3 describes a larger arc than the edge nearest that center. The result is that the minute marks made on the surfaces of the article criss-cross each other in every direction and they are not crowded together anywhere but on the whole are evenly spaced all over the surface.

The two gears 31 and 32 will control, by their relative numbers of teeth, the rate of progression of the work around the center. To change this rate they may be replaced by others having a different ratio.

Although I have illustrated and described only a single form of the invention and described only one use for it, T am aware of the fact that modifications can be made therein by any person skilled in the art without departing from the scope of the invention as expressed in the claims.

Therefore I do not wish to be limited to all the details of construction herein shown and described but what I do claim is 1. In a flat lapping machine, the combination with pair of lapping wheels held against rotation, one being adapted to rest on the work, of a cage located between the wheels and having means for holding a series of flat objects to be reduced on opposite surfaces, a central operating shaft below the wheels, a head located above the top of said shaft and adapted to be rotated on its own center, said head beii'ig arranged to be swung on center at one side of its center and the center of said shaft so as to be out of alignment with the shaft, means connected with the shaft for rotating the head on its own axis, and means on the heat for engaging said cage and rotating it with the head, whereby any point or article held by the cage will describea series of approximate circles in a plane progressively overlapping each other around the operative por tion of the wheels.

2. In a lapping machine, the combination. of an upper lapping wh el or plate and a lower lapping wheel or plate, the upper plate being adapted to rest on the work by gravity and to move down as the work is worn away, the upper one of said plates being held against rotation, of a cage for the work located between the plates, a head for rotating said cage, a central shaft, a support for the head movable to a position eccentric with respect to said shaft whereby the position of the cage can be adjusted to different distances from the center of the shaft and of the wheels, and means for rotating the head on its own axis in all its positions.

3. In a flat lapping machine, the combination with means for holding a pair of lapping wheels in stationary position, of a central stationary shaft, a gear on the shaft, a frame rotatable about said shaft, aparallel shaft carried by said frame and having two connected pinions thereon, one meshing with. said gear, a plate adapted to be swung about a center at the side to and from the position in which its center is directly in alignment with the first named shaft, a head journalled to rotate on said plate and carried thereby,

and a gear fixed with respect to the head and meshing with the second pinion about which it swings when the plate is adjusted, whereby the head will be rotated on its own axis in all its positions of adjustment.

4. In a lapping machine, the combination of means for holding. a pair of lapping wheels, a central stationary shaft, a gear on the shaft, a frame rotatable about said shaft, a parallel shaft carried by said frame and having two connected pinions, one meshing with said gear, a plate adapted to be swung to and from the position in which its center is directly in alignment with the first named shaft, a head journalled to rotate on said plate and carried thereby, a gear fixed with respect to the head and meshing with the second pinion, whereby the head will be ro tated on its own axis in all its positions of adjustment, a pair of pins extending from the head, and a work holding cage having means by which the pins will rotate it about the axis of the head.

5. In a flat lapping machine, the combination with means for holding a pair of lapping wheels in stationary position, of a central stationary shaft, a gear on the shaft, a frame rotatable about said shaft, a parallel shaft carried by said frame and having two connected pinions thereon, one meshing with said gear, a plate adapted to be swung about a center at the side to and from the position in which its center is directly in alignment with the first named shaft, a head ournalled to rotate on said plate and carried thereby, a gear fixed with respect to the head and meshing with the second pinion when the plate is adjusted, whereby the head will be rotated on its own axis in all its positions of adjustment, a pair of pins extending from the head, a work holding cage having means by which the pins will rotate it about the axis of the head, whereby when the head is located in eccentric position the work carried concentric with the center of rotation by the cage will move out and in as it is rotated on the axis of the cage and at any point thereon will describe a curve progressing around the center of the stationary shaft and also at all times constituting a part of a circle having a center moving around said center.

6. In a flat lapping machine, the combination with a pair of lapping wheels, one adapted to rest on the work, of a cage located between the wheelsand having means for holding a series of flat objects to be, reduced on opposite surfaces, a plate adapted to'be swung about an axis, a head journalled to rotate on said plate and having means for engaging the cage and rotating it about a center, and means out of line with said axis for rotating said head about its own center in all adjusted positions of the plate.

7. In a flat lapping machine, the combination with a pair of stationary lapping wheels or plates and a cage for holding the work between them, of means for rotating the cage by a compound motion to cause any point on an article held thereby between the wheels to describe a series of approximate circles in a plane progressively overlapping each other in a larger circle substantially of the cage.

8. In alapping machine, the combination with a pair of lapping wheels or plates, and a cage for holding the work between them, ofmeans for rotating the cage by a compound motion to cause any point on an article held thereby between the wheels to describe a series of approximate circles in a plane progressively overlapping each other in a larger circle, and of such amplitude as to move the opposite sides of each piece of work beyond the opposite edges of the operative surfaces of the lapping wheels.

In testimony whereof I have hereunto affixed my signature.

FRED G. MUNSON 

